Matthew Burr

hey, i've got an efi 302 with a rough rich idle that will occasionally die as well. i was told the vap can solenoid was bad and the egr valve was bad. but my understanding is the egr shouldnt be opening up at idle and after pulling the egr, it wasnt stuck but actually operates fine. If i idle the truck with the egr entirely disconnected so that it can suck air right in the hole on the throttle body it idles all the way up to 2000rpms but is relatively smooth. with it reattached the idle dips from 7-800 down to 2-300 and is very rich. if i pull the vap can hose it allows more air into the intake and smooths it out as well. i tried pulling codes but the reader says it couldnt communicate with the computer. i actually snapped a number of vac lines while i was reaching around them so i went ahead and rehosed them all since it was cheap anyways with no effect. also unplugging the map sensor has an effect on idle (seems to reduce the richness) but still very poor idle

O2 sensor? pickup coil? tps?

Matthew Burr

well, maybe an update will get someone to chime in a little bit

i pulled the throttle body and check voltage on the tps and the iac. the iac looks and physically operates like new and gets 11.5 with koeo and the tps gets .98 when the iac is unplugged. as soon as i plug the iac in it jumps to 1.34. so its not like i can run the rig without the iac attached, but does that indicate a wiring issue in the harness or at the ecu or is it normal to have the change in volts?

Chris_1

iTrader: (1)

I think you should be getting .9 to .96 volts at the tps with everything else plugged in. Maybe start with trying to adjust the tps into it's proper range - 1.34 would tell the computer you have your foot on the gas and it would provide fuel accordingly, which sounds like what your problem is the way you describe it ?

Matthew Burr

thanks for the reply, turns out its not going to make any difference, the rich smell is actually unburnt fuel because the guy whose rig i was working on finally informed me he had overheated it to the point it seized... so heads are toast